1. Field of the Invention
This invention relates to a multi-purpose implement for conducting dissimilar forest and soil management activities, including excavation and subsoiling (especially as related to soil productivity and restoration). The invention finds particular application in the decommissioning of forest roads, new temporary roads, skid trails and landings logging roads and in the growth and vigor of natural and planted trees and forage shrubs expected to grow on decommissioned roads. New impacts occur when equipment is brought into an area on a short-term basis, such as for fire-line construction, and the remedial treatment takes place shortly thereafter. The expression, “legacy compaction” as used herein refers to compaction from previous activities, particularly those involving operating heavy equipment on the soil surface. Examples of situations that lead to legacy compaction include repeated travel on road fill skill trails, dozer pile slash treatment and soil deposition from erosion that occurs over a work site at the toe of a hill. Whereas compaction from new impacts typically resides 4-18″ below the soil surface, legacy compaction may be deeper, and also may be accompanied by hardpan formation.
2. Description of the Prior Art
Following timber harvesting, restoration activities include obliteration of forest roads, new temporary roads, skid trails and landings and reduction of timber harvest legacy decompaction. Compaction has been associated with reduced mycorrhizal abundance and diversity in certain tree species, and also with ultimate growth rates and overall alteration of vegetation type. Restorative activities have conventionally required at least two pieces of heavy equipment and two entries. An excavator is used for the removal of culverts, creating waterbars, and recontouring of the road in sloped landscapes (excavation pullback of the fill slope). In a separate operation, subsoiling is done with a dozer pulling an agricultural subsoiling implement or dozer-mounted ripper system. This approach to subsoiling reduces compaction, but does not allow return of organic matter to the soil. Also, mats of organic matter tend to accumulate under the agricultural implement, resulting in a loss of organic matter from the soil resource. Moreover, the narrowness of forest system roads restricts the dozer-driven subsoiler movement to straight-line travel down the road being decommissioned. This may result in subsurface “piping”, leading to failure of sloping surfaces.
Attempts have been made to do the combined work with excavators using standard buckets, log tongs, and grapple rakes. Though decompaction is accomplished and organic matter returned to the surface of treated soil, the resultant soil profile becomes mixed rather than lifted. When re-contouring the road prism, subsoiling the ditch line is often left undone, primarily as the result of short-sighted economics. Unfortunately, neglect of subsoiling the compacted ditchline can lead to subsurface routing and transport of water moving across slope, rather than down slope, or to subsurface water impounding.
Buckets having attached ripper tools for multi-functional earth-moving capabilities have been disclosed in the patent literature. For example, Larson (U.S. Pat. No. 5,456,028) shows a backhoe bucket having a single ripper attached to the same coupling element that secures the bucket to the end of a hydraulically powered boom. The result is concentration of the force provided by the boom to the ripper tip. Larson depicts various embodiments for coupling the ripper to the boom, but none are amenable to use with a “quick change” connector (tool coupler). Moreover, the pivotal mount of the ripper to the back of the bucket is susceptible to eventual stress failure. In Pub. No. US 2003/0167661, Larson discloses an improvement in which the ripper is secured to a tool coupler to permit its use with a wide variety of interchangeable excavation tools.
Pratt (U.S. Pat. No. 6,490,815) shows an excavating bucket having a single ripping tooth or a pair of ripping teeth projecting rearwardly from the rear wall of the bucket. By virtue of this design, the motion for functional operation of the ripper is opposite that of the bucket. In making a sweeping motion, the operator is able to alternatively break up hard material and scoop it up for removal.